Data storage devices store digitally encoded information or data on a magnetic storage media. Illustrative data storage media include a rotating disc having a plurality of concentric data tracks. A head is positioned relative to one or more of the plurality of concentric data tracks via a positioning device such a voice coil motor, microactuator or other positioning device. In illustrative embodiments, the positioning device is energized to move the head between an inner diameter and an outer diameter of the disc or other storage media.
During an operational period, the disc is rotated and the positioning device is actuated to locate the head relative to select data tracks on the disc or storage media. For proximity or near proximity recording, rotation of the disc creates an air flow along an air bearing surface of the head. Air flow along the air bearing surface is pressurized to provide a lifting force so that the head “floats” above the data storage media or disc.
During non-operational periods, the device is powered off and rotation of the disc stops. For contact starts and stop devices (CSS), during non-operational periods, the head is parked on the disc or media surface. Typically, the positioning device locates the head proximate to a laser textured zone to park the head on the disc or media surface. The laser textured zone reduces head-media stiction so that when the disc is rotated, air flow along the air bearing surface releases the head to float above the media surface.
During a standby or idle period, when the head is not actively reading or writing data, a bias current is typically supplied to maintain a position of the head relative to the media surface. The head is typically biased away from the laser textured zone since contact between the head and the laser textured zone can damage the head, burnish the laser bumps and generate particles which can damage the transducer elements on the head. The head is usually biased proximate to a middle region of the media or disc so that following the standby or idle period, the head is not located beyond a guard-band signal or servo data proximate to an outer diameter of the media or disc. If the head floats beyond the guard-band signal or servo data, it will be difficult for the device to identify a current position of the head for seek operations following the standby or idle period.
Maintaining a bias current however requires power and for portable devices use of power during the standby or idle period can shorten the useful life or duration of the battery or other power source. Embodiments of the present invention provide solutions to these and other problems, and offer other advantages over the prior art. The above discussion provides background information and is not intended to be used as a basis for determining the scope of the claimed subject invention.